[whatwg] Re: Doctype FPI

James Graham jg307 at cam.ac.uk
Tue Aug 17 09:27:58 PDT 2004

On 17 Aug 2004, at 15:23, Ian Hickson wrote:

> On Wed, 14 Jul 2004, Terje Bless wrote:
>>> Yes. People rely on DTDs in a way which has led to millions of 
>>> authors
>>> to have a false sense of having done the right thing, when in fact
>>> their documents are sometimes worse than documents that are
>>> syntactically slightly broken but semantically fine.
>> Please try to examine that paragraph in an objective fashion. Your
>> language appears to be designed to evoke an emotional response
>> ("millions of authors", "false sense", "the right thing", etc.). If 
>> you
>> would like to make this point, I would appreciate it if you could 
>> recast
>> it in more neutral language so I can better understand it.
> Ok:
> There exist authors who use automated syntax checking tools based on 
> DTDs
> to verify the conformance of their documents, without understanding the
> limitations of such tools. These authors have, on occasion, written
> documents that are marked as valid by these tools, but that are 
> actually
> non-conformant. Such authors and documents are, in my experience, quite
> numerous.
> There also exist authors who do not use automated tools, but, through
> their understanding of HTML, create mostly correct documents. While 
> these
> documents often may have many validation errors, simple error handling 
> can
> usually recover the original intent of the author.
> It is my opinion that documents of the first kind are usually poorer, 
> in
> terms of general accessibility, than documents of the second kind. From
> this I assert that the limited ability for DTDs to detect conformance
> errors has caused harm.

I agree with your points but not the conclusion that you draw. In order 
to conclude that automated syntax checking tools (aka 'validators') are 
harmful, you must believe that the average quality of documents 
produced in the complete absence of a validator would be better than 
the average quality of the documents produced when a limited degree of 
automatic validation  is possible.
I strongly suspect that this isn't true. In the absence of a validator, 
authors who produce documents of the first kind ('valid' but 
non-conformant) would produce worse markup than they would produce with 
a validation service available since they lack knowledge of the 
language details and have no easy way of obtaining any feedback on 
their markup.
Authors in the second category (invalid but mostly correct) can often 
make small but worthwhile improvements to the quality of their markup 
if they use an automatic checking tool (obviously people who 
deliberately leave validation errors for some reason are an exception 
to this point).
Additionally, authors in the third, unmentioned, category; those who 
have a reasonable understanding of the spec but use the validator to 
detect and correct minor syntactic errors, would be harmed by the lack 
of a validator (this is a rather common category, especially among 
those who have grasped the style/structure separation of CSS and HTML 
and use a validator to detect small syntax errors in their markup that 
affects their style rules).

Your concerns can be somewhat alleviated by providing a validation 
service but:
Noting the limitations of the validator
Not providing a badge to indicate valid markup

>>> Schemas aren't much better.
>> In what sense? Your arguments above partly focus on DTDs inability to
>> specify datatypes and provide attribute syntax verfification, 
>> something
>> which Schema facilities seem to offer. Is your claim based on their
>> inability to provide semantic and stylistic verification?
> There are many aspects of even syntax checking that schemas are 
> currently
> unable to describe, although their abilities are indeed better than 
> DTDs'
> in this regard.

I should just note that I believe that incorrect semantics are often 
(perhaps even usually) more harmful than incorrect syntax.

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